A conventional connection device 9 for quickly connecting hose head 96 is shown in FIGS. 6 and 7, and generally includes an inner tube 91 which includes a top opening and an inlet member 93 is threadedly connected to the bottom of the inner tube 91. The inlet member 93 includes a valve unit 931 located in the inner tube 91. A first spring is connected between the valve unit 931 and the inlet member 93. An outer tube 92 is movably mounted to the inner tube 91 with a second spring 95 connected between the inner tube 91 and the outer tube 92 which is pushed and positioned at a first position by the second spring 95. A plurality of holes 911 are defined through a wall of the inner tube 91 and a bead 94 is movably engaged with each of the hole 911. The beads 94 are pushed inward by moving the outer tube 92 downward from the first position to a second position as shown in FIG. 6. When a head 96 of a hose is inserted into the top opening of the inner tube 91, the outer tube 92 is pulled downward and the valve unit 931 is pushed so that paths are formed to allow air or the like to be introduced via the hose, the inner tube 91 and the inlet member 93. After the head 96 of the hose is inserted into the inner tube 91, the outer tube 92 is released and pushed by the second spring 95 pushes the outer tube 92 upward so that the inside of the outer tube 92 pushes the beads 94 inward to be engaged with a groove in the outer surface of the head 96 to position the head 96. In order to ensure that the part of the head 94 protrudes beyond the opening 912 of the hole 911 so as to be engaged with the groove of the head 96, and to ensure that the bead 94 does not drop from the opening 912 of the hole 911, the diameter “L1” of the bead 94 can only be slightly larger than a width “L2” of the opening 912. The inner surface of the opening 912 is easily worn out by frequent movement of the bead 94, and the spherical bead 94 contacts the head 96 only at one point “P”. The point “P” is suffered by huge pressure and is easily worn out. Once the bead 94 and/or the opening 91 are worn, the head 96 is not well positioned. Shaking and leakage become the most concerns of the connection of the head 96 and the connection device 9.
The present invention intends to provide a connection device which includes oval-shaped beads which provide larger contact areas when contacting against the head of hose and the length of the beads is longer than the length of the holes in the inner tube so that the beads are not affected by the wearing.